Rear ABS rings for Audi A4, 1997

Hello!

The son of a friend wanted to "quickly" replace his rear brake calipers today.
Audi A4, manufactured in 1997.

He also brought along brake discs and brake pads. Ordered from the internet, just like young people do these days.

These are brake discs like the ones from the past, where the wheel bearings are pressed in. (I never thought they would still be installed this way on an A4.)
Well, he obviously didn't have any new wheel bearings, so I called his father and told him to go to the next auto parts store to get some more wheel bearings.
It worked out, and while I was working on it, it occurred to me that there are still the ABS sensor rings there.
So, I called the dealer right away to make sure he includes the bearing rings in the sale.

Everything worked out. He then brought the wheel bearings and ABS sensor rings, and we had already disassembled the brake system quite a bit.

The original donor rings were made of sheet metal, while the new ones are solid steel.

"Okay," I thought. "It looks sturdy, and it fits." The number of teeth, etc., also matches.
I pressed the wheel bearings in, and I also installed the sensor rings.

Fortunately, I have to say, I then double-checked the distance between the ABS sensor ring and the sensor.
Too big.
Perhaps 4 mm.
This isn't going to work.

I managed to get the rings back on gently, hopefully without bending them.

I somehow need to get it perfectly positioned and perfectly round.
This will require patience...

How do you do something like that properly?
Can someone please tell me the distance to the sensor?

I can actually get quite far with a basic understanding of a sensory perception theory.

What kind of ridiculous construction is this?

It seems to me that the donor rings must be pressed into the exact correct position using a special machine or device, which may be the case in mass production.
But as a craftsman, you're really good.

Hi Steffen,
Without a guide, you're completely lost here.
Could you tell me the engine type, as well as the MKB and GKB codes? And a few photos.
Maybe then you'll be able to make progress.
hg
Herbert.

Hello Steffen,

Audi uses a simple sleeve to press the rotor onto the wheel hub.

Tool VW 32-119.

After adjusting the bearing preload (the pressure plate must remain movable laterally), the central nut is tightened in two steps.

1. 115 Nm

2. 180-degree rotation angle.


Best regards,

Michael.

Hello!

I'd like to share how things turned out:

So, the car is finally put back together and working properly again.

I don't have any vehicle data right now, and it's not necessary anymore.
That was a 1997 model, gasoline engine.

In the picture, you can see the black sensor ring for the ABS system. It was something that could have been purchased pre-assembled, but it wasn't.

This brake-wheel bearing assembly is constructed in a similar way to the wheel bearings found in Golf 1, Golf 2, and Golf 3 models, using a classic design with tapered roller bearings. The outer storage compartment was larger than it used to be in the older 2-door Golf models.
The oil seal has an additional dust lip on the outside, which makes it more difficult to install.
I adjusted the wheel bearing exactly as I'm used to from previous experiences with Golf 2 models, etc.

Okay, I then carefully adjusted the toothed rings into the correct position, achieving a runout of less than 0.1 mm and a distance of 0.5 mm from the ABS sensor.

The correct approach would have been to use a flat plate and turn an aluminum ring that is approximately 10 mm high, but I didn't have suitable material available.
I could have used that to press something properly. However, it's also difficult to accurately measure whether it's exactly 10 mm or 9.5 mm beforehand.
Once the oil seal was in place, and since I didn't have a new one, it just wouldn't work. It would have interfered with the pressing process.
So, it's quite a flimsy construction.

As a small addition:
When installing new brake calipers, it's necessary to bleed the brakes.
I then said, well, so far, the brake fluid reservoir has only burst once, and I'm going to reduce the pressure to 0.9 bar. Because of the old car...

And as I said, I turn the valve on the bleeder device, and of course, a jet of brake fluid immediately shoots out from the container, through the ventilation slots in the hood, and all over the roof.
The sunroof was, of course, open.

In other forums, there's a "black museum" dedicated to failures. "Bad luck and mishaps."
That's where this post would fit in.

So, we ended up having to bleed the brakes the old-fashioned way, using the brake pedal.
It worked, though. I told him three times to please not press the brake pedal all the way down, let's see if he did it.

Hi Steffen,

Does the "stub" of the wheel bearing housing that interfaces with the brake disc have a flange that, after the rotor is pressed on, sits flush with the inner edge of the rotor (as visible in your picture)? This would explain the purpose of the simple tool 32-119. Press until the tool is flush with the stop.

Otherwise, there would either have to be a gauge or a stop for the rotor.

Besides, since I don't have a press, I always run a threaded rod through the center whenever possible, and use appropriate plates or rings to secure it.

hg
Herbert.

As I said, the wheel hubs have sensor rings, specifically the original ones that are simply knocked out by drilling through the holes for the wheel studs.

The distance to the sensor is adjusted using the sensor itself, which is loosely mounted in a sleeve... adjust it all the way until it's flush, and then pull it back just a tiny bit.

To install the sensor ring, I use an outer ring from a wheel bearing that I've taken from my collection of spare parts. I place a flat piece of iron on top, align it carefully, and then use strong blows to press the new sensor ring into place. Of course, the old sensor ring is cleaned of any rust beforehand.

Furthermore, there are different rear wheel bearing variants for the A4 B5, and a change occurs around 1997, so it's important to pay attention to that as well.

Additions because I only quickly posted to the forum yesterday